First, the bad news: viewers must wait until October 21 for a new episode of The Vampire Diaries.

Now, the good news: this week's "Kill or Be Killed" gave us so many shocks and developments to ponder that we'll have plenty to discuss until then.

When the next installment does air, we'll be treated to the return of Bonnie and Alaric, both of whom were absent last night. We'll also hear Katherine warn Elena about a "plan B." Consider what this may entail as you watch the preview below:

[video url="http://www.tvfanatic.com/videos/pan-b-promo/" title="Plan B Promo"] [/video]

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.